The last few decades have witnessed a dramatic increase in the use of code symbol readers, such as barcode scanners, in business applications. Businesses have particularly gravitated toward the use of code symbol readers in the inventory management and point-of-sale contexts. Code symbol readers are electronic devices that read code symbols, such as barcodes, QR codes, matrix codes, or other computer-readable indicia. Most code symbol readers have a light source, a lens, and a light sensor for converting optical signals into electrical signals. Typically, the light source projects a laser onto the code symbol, which then reflects the light back in an optical signal that is converted by the light sensor into an electrical signal. The electrical signal is then decoded to obtain the information represented by the code symbol.
Broadly speaking, code symbol readers can be divided into handheld code symbol readers and stationary code symbol readers. A user can move a handheld code symbol reader into a position for reading a code symbol affixed to an object. In contrast, the object bearing the code symbol must be moved into a position where it can be scanned by a stationary code symbol reader. Both types of code symbol readers are often encountered at point-of-sale locations in the retail environment. Grocery stores typically employ stationary code symbol readers, over which employees swipe purchased items for scanning at the checkout station. Other retailers often utilize handheld scanners that allow their employees to move the codes symbol reader into position for scanning a code symbol on an object that might not be suitable for passing along a checkout table (e.g., a large and/or heavy object).
With both handheld and stationary code symbol readers, it is often advantageous to initiate the scanning process only when an object bearing a code symbol is present within the code symbol reader's field of view. By only turning on the laser source when an object is within the field of view, for example, the code symbol reader saves power and extends its usable life. Many code symbol readers incorporate object detection techniques to detect when an object is within the field of view of the code symbol reader. When an object is detected, the scanning process is initiated—by powering up the laser, for example. Typically, the code symbol reader continues its scanning operations until a successful scan or until the expiration of a timeout period, whereupon the code symbol reader returns to a standby mode to await the next detection of an object within its field of view.
The object detection feature often has limited configurability. Typically, the user may be able to set the object detection range to either a short setting or a long setting. In the short-range configuration, the scanning process is initiated only when objects are detected that are relatively close to the code symbol reader (e.g., about 5 inches away). In the long-range configuration, the scanning process is initiated only when objects are detected that are relatively far from the code symbol reader (e.g., about 20 inches away). Because code symbol readers may need to scan code symbols that are positioned at distances that may not be congruent with either the short-range or long-range configuration, code symbol readers having this limited ability to configure the object detection feature are often unsatisfactory.
A need exists for a system for reading code symbols that can be customized to detect objects located at varying distances along a continuum of distances from the code symbol reader. A need also exists for a method of configuring the object detection subsystem of a code symbol reader to detect objects at varying ranges from the code symbol reader.